Altered glycosylation of glycolipids, glycoproteins, or proteoglycans are frequently observed in tumor tissues and cultured cancer cell lines. These changes have diagnostic use but also can contribute to the ability of tumor cells to grow, induce neovascularization, metastasize, and avoid host immune surveillance. We are primarily intereseted in sulfated glycoconjugates and their interaction with extracellular matrix and cell surface adhesion molecules. These include thrombospondin, laminin, selectins, and apolipoprotein E. Human small cell lung carcinoma cell lines are used to examine expression and function of novel sulfated glycolipids. These glycolipids interact with thrombospondin and contribute to adhesion of SCLC cells on a thrombospondin matrix. Sulfated glycolipids on these cells are also being examined as potential ligands for selectin-mediated adhesion of SCLC cells to activated endothelium. Heparin oligosaccharides are being used to define the molecular basis for interactions of heparin and heparan sulfate proteoglycans with two binding motifs on the thrombospondin molecule and on a second heparin-binding protein, apolipoprotein E. Inhibitors of these interactions are being tested for effects on angiogenesis and tumor growth.